1. Technical Field of the Invention
The present invention generally relates to internet protocol (“IP”) routers. More particularly, and not by way of any limitation, the present invention is directed to an architecture for implementing multi-time scale adaptive IP routers.
2. Description of Related Art
The deployment of complex value-added services on the Internet requires support for appropriate time-scale resource management and control on an on-going basis after the initial setup time of the network. Frequent interaction between services and the network calls for identification and implementation of sophisticated mechanisms that can allocate resources (e.g., links, switch capacity, etc.) optimally, isolate or dynamically share resources in a controlled fashion among various users, and change the use and allocation of resources in response to changes in conditions of the network and user requirements over time.
For QoS adaptation, the most developed adaptive resource allocation in IP is based on end-to-end feedback systems, such as TCP and ATM congestion control. In end-to-end feedback systems, the receiver must inform the sender that there is a problem when it arises. The main drawback to such systems is that often by the time adaptation has occurred, the condition might already have changed. Accordingly, such systems are typically not sufficiently fast.
Adaptation of the switching node behavior on the basis of DiffServ, Per-Hop Behaviors (“PHBs”), and variants of Random Early Detection (“RED”) are commercially available. With these, policies and priorities are associated with the packets. When congestion occurs, packets are selected for dropping based on these policies and priorities. However, these are neither measurement-based nor are they designed to work in a coordinated fashion at multi-time scale.
IEEE has proposed a standard (IEEE 1520) that brings layering of IP router functionality for programmability and adaptation. This standard defines an overall infrastructure, but not a method or system for performing adaptation. The ForCES working group in IETF has proposed ideas that separate the control elements from forwarding elements in a way that can help introduce dynamic behavior at the node level. Also, network equipment manufacturers are currently beginning to support measurement-based adaptation. However, none of the foregoing solutions support implementation of a multi-time scale adaptive router.